Electric switch



Dec. 29, 1942.

c. APPELBERG 2,306,585

ELECTRIC SWITCH AFiled July 21. 1959 Patented Dec. 29, 1942 ELECTRICSWITCH Carl Appclherg, Stockholm, Sweden Application July 21, 1939,Serial No. 285,795 In Sweden August 16, 1938 1 Claim.

The present invention relates to electromagnetically operated switchesof the kind in which the break contacts together with the electromagnetarmature are disposed within an evacuated or gas lled, substantiallytubular container. The novelty of the invention consists therein, thatthe break contacts together with the motive members serving to actuatethese contacts are mounted on a stand placed into the tubular container,which stand is intended to be introduced into the container from one endof the same so as to bear laterally on the walls of the container, whilethe electromagnet armature and the xed terminal contacts insertedthrough the container are disposed on both sides of said stand atopposite ends of the container. Owing to this arrangement, the variousparts of the switch can be easily mounted and adjusted before beingplaced into the container. Moreover, in this way the apparatus can bemade extraordinarily compact so that the switch may in its entirety beenclosed in a tubular container having a comparatively small diameter,which fact is of great practical importance in many of those cases, inwhich electromagnetic switches of this kind are primarily intended to beused.

The invention will be more closely described with reference to theaccompanying drawing, in which Figure l shows an embodiment of a switchaccording to the invention, Figure 2 shows a modication of the motivemechanism, Figure 3 shows a further modiiication of the motivemechanism.

Referring to Figure l, the reference numeral I5 designates ahermetically sealed vessel or conl tainer which is either evacuated orcontains a suitable inert gas. Within said container the different partsof the switch are arranged on a frame I5 oi Steatite or other insulatingmaterial. rihe stationary contact I1 is connected by means of a lixedmetal blade I8 with the inner end of a metal wire I3 melted into theglass wall, thev end of said metal wire positioned externally of thecontainer forming one terminal of the switch.

The movable Contact 28 is carried by a Contact (Cl. 20G- 87) two-armedlever 25 which is journalled on a pin 26 xed to the frame and which,through the intermediary of a roller 21 provided at the end of one ofits arms, presses against an extension of the contact arm 2| under theaction of a spring 28 one end of which is secured to the lever at thepoint 29 and the other end of which is secured to the frame at the point30. The spring 28 is so dimensioned as to be capable of swinging theContact arm 2| counter-clockwise While compressing the spring 24.

An electromagnet armature or iron core 35 in the form of an open-endediron cylinder is guided for rectilinear movement in the container I5 andis adapted to be actuated by an electromagnet coil 35 providedexternally of the container. A link 31 serves pivotally to connect thearmature 35 with the two-armed lever 25 at the end thereof which isopposite to the one carrying the roller 21.

The electro-magnet coil or solenoid 36 and the armature 35 are sodimensioned that upon energizing of the coil the armature will be pulledinto the latter, the lever 25 being then rotated counter-clockwise Whiletensioning the spring 28 until the lever comes to bear against a stoppin 33 secured in the frame. This will permit the movable contact arm 2|to rotate clockwise under the action of the spring 24 until the movablecontact 20 engages with the stationary contact |1. The movement of thetwo-armed lever 25 under the action of the armature is interruptedthrough the engagement with the stop pin 38 only after a certain playhas been produced between the extension ci the contact arm 2| and theroller 21, the fixing points 29 and 33 of the spring 23 being sopositioned that the turning force exerted by the spring on the lever 25is successively reduced according as the armature 35 is pulled into thecoil 35, so that said turning force will be a minimum when the lever 25engages with the stop pin 33 upon complete attraction of the armature.

When the operating current passing through the coil 36 is interruptedthrough the opening of a contact, not shown, provided in the operatingcircuit, the lever 25 is turned clockwise with an increasing force underthe action of the spring 28, the armature being then pulled out of thecoil while getting an increasing momentum, until nnally the roller 21strikes against the extension of the Contact arm 2|, swinging the lattercounter-clockwise against the action of the spring 24 whereby themovable Contact 20 is removed from the xed contact I 1.

As will be clear from the drawing the movement transmitting systeminserted between the armature 35 and the movable contact 2i) is sodimensioned that the armature moves a considerably longer distance thanthe movable contact coupled therewith in that, on the one hand, theangle lever 25 is provided with arms of considerably dii'erent lengthand, on the other hand, said angle lever actuates the swingable contactarm 2l at a point which is positioned farther away from the pivot 22than is the movable contact 23.

The extension of the contact arm 2l forms together with the angle lever25 a cam device the two mutually cooperating parts of which are out ofengagement with each other when the armature takes up its attractedposition, involving that the cam device operates with a certain play.

According to Figure l, the desired reduction of movement of the movablecontact has been t obtained mainly througha suitable dimensioning of thelengths of the various levers; of the coupling. It should be. clear,however, that a con, siderable part or even the greater part o f' thedesired movement reduction can be included in the cam device proper. Forexample, the angle lever 25 can be designed soA that the line betweenthe swinging axis 26 and the point where theV roller 21 engages with theextension of the contact arm 2l forms a greater angle with the saidextenl sion, thereby reducing, for a certain turning of the angle lever,the componentv of movement of the roller which is perpendicular to theextension.

An embodiment in which the main part ofr the movement reduction isincluded in the cam, device is shown in Figure 2. According to thisyarrangement the movable, cam member consists of a one-armed lever liiwhich is pivotally; mounted at one of its ends on a shaft 4l secured inthe frame. At its free end the lever carries a roller 2. At a pointbetween the shaft 4l and the roller 42 the lever 4i] is connected bymeans of a link 43 with the electromagnet armature 35'. A spring 44normally holds the lever, 40 in engagement with a stop pin 45 secured inthe frame. Upon energization of the coil 36 the armature 35 will bepulled into the coil, the lever 40 being then swung clockwise whiletensioning the spring 44, causing the roller 42 to strike against a bentextension of the movable contact arm 2i, which serves as the xed cammember, and to roll along said extension while swinging the contact armcounter-clockwise against the action of the spring which actuates thesame. By suitably shaping the bent extension each desired ratio betweenthe movement of the armature 35 and the movement of the movable Contact20 may be obtained.

The switch according to Figure 3 differs from the one just describedsubstantially only therein that the extension of the Contact arm 2iserving as axed cam member carries a roller 46, whereas the curved camsurface is provided on the movable cam member 41, the latter being madein the form of a single-armed lever.

It. is believed in view of the foregoing description that a furtherdetailed description of the operation; of the invention is unnecessary.Likewise it isbelieved that the advantages of the inventionwill' bereadily apparent.

Having thus fully described the invention what is claimed as new anddesired to be secured by Letters Patent is:

An electric switch comprising in combination, a hermetically` closedtubular container, a magnet coil arranged outside the container, aspring actuated armature longitudinally slidable inside the container atone end thereof, electrical terminals extending; into the container atthe opposite end thereof, a switchl frame mounted in an intermediateportion oi the container, switch contacts mounted on said frameincluding acontactl arm s wngable transversely of the container and extending longitudinally into a spacel provided be'- tween the switchframel and the armature, and a Contact operating mechanism mounted insaid space onthe end of said frame and adapted to be actuated by thearmature to shift said contact arm.

CARL APPELBERG.

